<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        var user = {
            "username": "vivian",
            "age": 20,
            "info": {
                "telephone": "123456",
                "cellphone": "987654"
            },
            "address": [
                {
                    "city": "beijing",
                    "postcode": "222333"
                },
                {
                    "city": "wuxi",
                    "postcode": "555666"
                }
            ]
        };

        window.onload = function () {
            alert(user.username);
            alert(user.age);
            alert(user.info.cellphone);
            alert(user.address[0].city);
            alert(user.address[1].postcode);

            user.username = "changjing";
            alert(user.username);
        };
    </script>
</head>
<body>

</body>
</html>